Environmental Health

As the Environment Gets Healthier, So Do We

People born today, on average, have a life expectancy about twice that of folks just over a century ago. Most of those additional years have been gained by healthful environmental changes - including improved sanitation, purified water, cleaner air, the safer use of chemicals in our homes, gardens, factories and offices, and the restriction or elimination of unsafe practices.

In other health-promoting environmental steps, the United States and its states and cities, businesses and unions have worked together and:

Removed lead from gasoline, and redesigned the gasoline pump to expose you to less benzene, which might increase your risk of cancer.

Reduced smog, making your breathing easier.

Removed from the market questionable products, such as a laxative ingredient that tests showed could cause cancer.

Restricted or removed from commerce many workplace chemicals, food dyes and pesticides because they posed a risk of sterility, cancer or other diseases.

In each case, these preventive measures did not just happen. They were put in place following studies by the National Institute of Environmental Health Sciences, the National Toxicology Program (which is headquartered at NIEHS) and/or similar laboratories.

Great progress has been made since the 1962 book Silent Spring by Rachel Carson forecast that persistent pesticides would silence the world's birds - and perhaps make the world unlivable for humankind as well.

The book produced public support for the creation of NIEHS for research and, soon afterward, for the creation of the regulatory Environmental Protection Agency. Public support also developed for the creation of the National Toxicology Program. As one result of the interest and the ensuing research, DDT, dioxin, PCB's and other harmful and persistent chemicals have been banned in the United States and many other countries. These and the rest of the "dirty dozen" chemicals linked to cancer, birth defects and impaired reproduction are being curtailed internationally as well, under the Stockholm Convention on Persistent Organic Pollutants, to which the United States is a participant.

Progress has also been made in how we think about environmental health. Today, the environmental health sciences aren't entirely about pesticides and other chemical pollutants in our air and water. The definition of "environmental health" has broadened to include the environment we create for ourselves (by smoking or not smoking, and by our diet, for example). It also includes the medicines and other therapies we are prescribed, our occupations and places of work, and our lifestyles: Are we couch potatoes or joggers? Sexually reckless or responsible? Listening to loud music or keeping the volume down?

Some scientists even believe that a good view of nature, as opposed to a brick wall, may have a positive effect on our health.

The environmental health sciences also look at socioeconomic status - that is, how the workplace, neighborhood and home environment of many poor Americans produce disease, disability and premature deaths.

Ironically, though today's pesticides are safer and our air and water cleaner, the new, broader definition of environmental health adds to the numbers of diseases that are considered to be related to the environment. For cancer, the environment-related contribution has thus "increased" from an estimated 3 or 4 percent or so, when synthetic chemicals were the issue, to as much as 80 percent under the broader definition.

There has also been a revolution in how we measure and study the impact of environmental agents on our health. Indeed, the chemists and water-testers of yesterday would be surprised by the scenes at environmental health research centers today:

Cloned human genes are being set out in clusters on a glass slide to test suspect poisons. In the future, such techniques - using clones of your genes - may help predict how you, as an individual, will react to a drug or other chemical.

The blood and urine of groups of people representing the population as a whole are being tested to see what chemicals these people have individually absorbed.

And the genes of similar, representative groups are being studied to see what slight changes in their so-called "susceptibility" genes make them more - or less - susceptible to cigarette smoke, industrial chemicals, pesticides and sunlight.

The environments we personally create for ourselves, through our habits, diet and lifestyle are now seen as very important.

Environmental health has taken a new turn now that the human genome has been sequenced or "mapped." The environmental health sciences have taken up the advanced tools of genetic research and moved into a new phase that intrigues many of our best scientists.

At what point does the cell tip toward cancer, Parkinson's or Alzheimer's?

We and others are reaching deep into the human cell to find the changes that, in response to an environmental assault, tip that cell toward cancer, Parkinson's, Alzheimer's or other diseases. We are re-sequencing, or re-mapping, the human genome in a cross-section of Americans so we can see how their genes vary and how those variations make some people more susceptible - and others, less - to the substances around us.

This kind of research is so new, so cutting-edge that scientists often have to compound new words (like "toxicogenomics") to describe what they're doing. Yet it is typical of what goes on today at the National Institute of Environmental Health Sciences and the National Toxicology Program. This whiz bang work - alongside more traditional studies of lead poisoning, pesticides, mercury and diesel exhaust particulates - is also carried out by the NIEHS' 20-plus university-based centers in communities across the United States, from Boston's Harvard to Berkeley, Calif., and from New York's Columbia University/Harlem, to the Mexican border work of Texas A & M.

Whether you're a healthy man or woman - or one facing prostate cancer or Parkinson's, breast cancer or Alzheimer's - whether you're a couple with children - or having no success in conceiving them, the new environmental health sciences are important to you.

Technologies developed for the international genome project are now being used to study toxins and other environmental factors, and our susceptibility to them.

"If you want to learn about the health of a population, look at the air they breath, the water they drink, and the places where they live."
- Hippocrates, the Father of Medicine, in the Fifth Century BC.